Lamp



1952 G. F. EMBSHOFF ET AL ,6

LAMP

Filed July 14, 1950 5 Sheets-Sheet 1 ATTORNEYS 1952 G. F. EMBSHOFF ETAL 2,613,328

LAMP

Filed July 14, 1950 5 Sheets-Sheet 2 i g j INVENTORS Z W W; I

06mm, ATTORNEYS Oct. 7, 1952 s. F. EMBSHOFF ETAL 2,613,328

LAMP

Filed July 14. 1950 S-Sheets-Sheet 3 ,W w v M 7 ATTORNEYS 1952 G. F. EMBSHOFF ETAL ,328

LAMP

5 Sheets-Sheet 4 Filed July 14, 1950 VENTORS ATTORNEYS.

Oct. 7, 1952 G. F. EMBSHOFF ETAL LAMP 5 Sheets-Sheet 5 Filed July 14, 1950 QNDN 1N VENTORS ATTORNEYS Patented Oct. 7, 1952 LAMP George F. E'mb'sliofi; Hamilton. County, and George Sperti, Cincinnati, Ohio, assignors to. The Institutum Divi .Thomae Foundation, CincinnatLOhio, an Ohiocorporation not for profit Application J My 14', 1950, Serial No. 173,824

This invention relates to lamps ofthe type sold:

to the general public for household useas sun lamps and including a source of ultraviolet ra fiiClaima, (Cl. 250'85') diation and preferablyalso a source: ofinfrared. 7

radiation.

The usual method of-providing-ultraviolet ra diation in sun lamps is to operate-a mercury vapor arc in series with a suitable ballast resistance, which may be designed to provideinf'rared radiation if desired. Such lamps are illustrated for example by the-prior U. Si Patent No:

- 2,369,987 and also by thecopending application:- of George F. Embshoit, Serial No. 52,363, filed October 1, 1948. The desirable and beneficial ultraviolet wave lengths areithose longer 'th'an about 2800 Angstroms, whereas. shorter wave lengths. mayv have harmful eifectsi Since. the spectrum of the mercury arc emits substantial amounts of energy at these undesirable shorter wave lengths, the usualpractice in: sun lamps is to enclose the arc in glass which filters out most if not all of the radiation below about..2800: Angstroms. On.v the. other hand, as the operating emperature and vapor pressureinwthez arc increase, the ultravioletenergy outputtin the region of the desirable longer wave lengths mentioned above also increases. Hencefor sun lamppurposes, it is desirable. toutilize theheat-developed by the ballastresistancenot only to. provideinfrared radiation but alsoto increaSetheoperat ing temperatureof the arc and with it the va por pressure as rapidly as possible. These efiectsare facilitated when: onev or" more elongated: ballast:- resistors are arranged parallel" with and closely.

adjacent: to a. tubular: are burner,- whereby-"heat losses are minimized. and the ballastxheat -is distributed more; or less ."llIlifOll'IllY- throughout. the length of thearc as disclosed in. the aforesaid Embshorf. application;

The present invention relates: to alamp of: the

type characterized above; and: oneioirit'sobl'ects;

is to provide an improved lampsofrthis type :in-

the form of a portab1e1unit...for household-use which is simple and inexpensive in construction, which is convenient to handl'eanduserand which produces an effective .outputof both ultraviolet radiation and infrared. radiation. onoptionallyof infrared, radiation only.

Another object is to-providea lamp of'the type characterized above having improved means for housing the ballastresisto'r elementsan'dfor -uti-"-- lizing the heat developed thereby to improve-theoperation of the are burner;

Another-object. is to providealamp of thettype characterized above embodying anovel combination and arrangementof ultraviolet generator, infrared: generator andreflector whereby both types of radiation are effectively-combined-andradiated from the lamp.-

A; further. object isrto provide an improvedre type characterizedabove having improved means. for mounting the. burner tube/and the. resistor elementor elements in association with the. re-

flector' which: suitably directs the emitted radlae tion.

A still'further' object isto provide an. improved housing for: a lamp of the. type. characterized aboveihavlng a base and a relatively movable cover unit comprising. a reflector,. an ultraviolet lampor burnen: and suitable ballast resistors, said: cover. unit being movablerelatively to the base to: an open position. for operation of the.

lamp. and tea closed position in vwhich the operating parts.aresubstantially completely enclosed.

In a. lampxof the type described above, the glass" walls. of the burner tube are exposed. to considerable heat and care; must be taken that they do not reach a temperature at which the glass: softens and the tube is damaged or destroyed; The danger of overheating isincreased I as the mercury vapor pressure increases and'the. are changes from adifiused glow to a concene trated; stream, because of the frequent tendency of such concentrated'arc streams to. followa bowed or curved path between the electrodesand. thus to approach closely to-or even to touch the Another object of'the invention is to overcome this; tendency and to:

lass wall of the tube.

confine. theconcentrated arc stream more or lessclosely to a straight axial path.

Other objects. will appear hereinafter description of the invention proceeds.

Two embodiments of the invention have been illustratedin the, accompanying drawings, but it is to be-expressly understood that such drawings are for purposes of illustration only and are not. to be taken as a definition of the limits ofthe invention, reference being had to the appended v claims for; this purpose.

In thedrawings;

Fig. 1 is-a side view'of a lamp embodying the invention inits operating position:

Fig. 2 is airont view of the lamp shown in" Fig. 3- is a section on themm 3 .3, of.

Figs. 4 and 5 are sections. on'the lines 14.245.

Fig; 6: is a section on the line tie-'6. of.

physical arrangement and electrical elements;

as thev Fig. 13 is a wiring diagram;

Fig. 14 shows a different are tube construetion embodying the invention; a

Fig. 15 is a section on the line I-I5 of Fig. 14; Fig. 16 is a diagram explanatory of the design of the reflector;

Fig. 1'7 is a transverse section through the reflector;

Fig. 18 shows somewhat diagrammatically the appearance of the reflecting surface; and

Fig. 19 illustrates the operation of the reflector.

A lamp embodying the invention comprises a housing formed in two parts capable of substantially completely enclosing all of the operating elements of the lamp when not in use as described hereinafter. base which may be made of any suitable material such as metal, molded plastic, rubber or the like, and which may have any suitable shape, this base preferably being recessed or dished to form a larger housing cavity. The other housing part comprises a cover unit pivoted to the base at one end on a horizontal axis to swing from a more or less upright open operating position downwardly into juxtaposition with the base to close the housing. This cover unit includes all of the essential operating parts of the lamp, comprising a substantially tubular ultraviolet arc burner and a suitable resistance means which serve as ballast for the arc and also for emission of infrared radiation, the lamp and the resistance means being assembled rigidly with a suitable reflector and these parts being partially enclosed by an outer cover element that is shaped to cooperate with the base and that may be made of any suitable material similar to or the same as that of the base.

In the form shown, the base comprises a pressed One of the housing parts forms a or stamped sheet metal pan of more or less oblong shape with rounded ends or corners, the base having a peripheral wall I adapted to rest on a supporting surface, a substantially flat horizontal margin 2, and a recess or cavity 3. The cover unit is secured to this base at one end by any suitable type of pivot mounting- For example, a bracket 4 is secured to one end of the base I, said bracket having upwardly extending ears or lugs 6 which fit between corresponding ears or lugs 6 of a second bracket I, the. tWo brackets being pivotally connected by means of a pivot pin 8 passing through the lugs and held in place by rivets 9. The cover unit, which is indicated generally at ID in Figs. 1 and 3, is connected to and carried by the bracket 1 of the pivot mounting in any suitable manner as described in detail hereinafter.

The ultraviolet lamp or burner forms part of the cover unit I0 and is preferably of the same general type as those disclosed in the 'prior patent and application mentioned above, its detailsbeing illustrated in Figs. 3 and 6-10. As'shown in these figures, the glass wall II of the burner is substantially tubular in shape and is suitably closed and sealed at each end as by means of stems and presses I2 of the usual type. This bulb contains a quantity of vaporizable and ionizable material such as mercury, and is usually filled with argon or other suitable rare gas at a low pressure. Preferably the quantity of mercury employed is limited so as to prevent the development of unduly high mercury vapor pressures when the lamp is in operation. Mounted in the press I2 at one end of the lamp is a wire or conductor I3 leading to an arc electrode I4. A

press I2 at the opposite end of the lamp and leads'to an arc electrode I6; Filaments I1 and I8, which are preferably coated with or otherwise embody a suitable electron-emissive substance,

straight axial path between the electrodes andv thus to approach closely to, the glass wall II. In:

order to avoid possible softening of the glass due: to such bowing, arc centering means are preferably provided between the two electrodes I4 and I6. These means comprise one or more arc cen-- tering devices 2| each provided with a central aperture through which the arc stream passes, and are electrically disconnected from the electrodes and filaments mentioned above, being supported in the bulb in any suitable manner as by attachment to the tubular wall II or to the presses I2. The are centering devices may comprise discs of metal or of refractory nonconductive material such as ceramic or, as in the form shown, loosely wound spirals of refractory metal wire such as molybdenum and the like.

The ballast resistance for the are preferably takes the form of an elongated unit arranged parallel with and closely adjacent to the tubular ultraviolet burner, so that'the heat developed in the ballast is distributed uniformly throughout the length of the lamp as explained above. Also this unit is preferably mounted between the burner tube and an associated reflector all of which elements formpart of the cover unit I0, this arrangement avoiding interference with direct radiation of ultraviolet light and at the same time resulting in the reflection of both ultraviolet radiation and infrared radiation and the distribution of the radiation from both sources over substantially the same area as described hereinafter. Theelectrical characteristics usually -make'it desirable toemploy two ballast resistors for this purpose,'each having a length equivalent to that of theare tube, these resistors and the arc path between the electrodes I4 and I6 being connected in the operatin circuit of the lamp so that the resistors are in series with each other and with the arc path. A starting circuit may also be connected across the filaments I1 and I8 externally of the lamp bulb to assist in starting the are as described below. In case it may be desired tooperate the lamp as an infrared generator only, .9, third resistor and switch are connected in a circuitin shunt to the electrodes I4 and I6. These resistors are combined in the single elongated unit-mentioned above.

The connections.v between the elements mentioned above and the operating circuits will be better understood from Figs. 12 and "13. The lamp is energizedlbyinsulated supply lines 22 and 23, preferably in the form of the usual supply cord 24 Inside the lamp, the supply lines are separated and the line 22 leads to a binding post 25 from which a connecting wire 26 leads to one end of a ballast resistor 2'! which is parallel to and of approximately the same length as the lampbulb; I I.- The other end of the resistor 21 is connected by a wire 28 with the adjacent end of a second resistor 29, also similar wire or conductor I5 isrnounted inthe -;paralle1 to and of substantially the same length as the lamp bulb I l', and the. other end of the resistor 29is. connected by aconductor 30,.with a binding post '31. .A conductor-3 2 connects the. binding post 31. with the lead-in. Wire13 and the electrode l4. At. the opposite. end. of, the lamp, the electrode [6. and its leadkiri .wire l5 are connected at 33" with awire 34 passing through one side of. a double insulating tube 3.5 of ceramic or like material and thence to a binding post 36 at the other. end of the lamp; the line conductor 23 beingconnected to thi's'bind ing post. Reference to Fig; 13shows' that in the normal operation of the lamp, the currentiiows through a series operating "circuit comprising conductors 22 and 26, resistorflfwiregzs, resistor 29, wires 3i), 32 and I3, .electrodestld andflli',

wires i5 and 34, and-lineaconductorit.

The are may be started either automatically or manually. In theform shown, the/starting circuit includes the filament lead-inconductor i9 which is connected to asuitably insulated wire 31 leading to one terminal-38 of a m'anual starting switch indicated generally at 3 9 the other terminal'Ml of this switch being connected to a suitably insulatedwire M from which a wire '52 leads to the opposite end of the lamp where it passes through an insulating tube of ceramic or like material and is thenconnectedlats liwith the filament lead-in conductor 21!. Thestarting switch 39 is of any suitable typewhich normally remains'open but can be-held closedilong enough to start the operation of: the lamp. Referring to Fig. 13, the starting currentpassesnfromline conductor 22 through wire; 28.. and resistor: 27, wire 28 and resistor29,wires 39,32; and. l3.,,fila.-

ment ll wires l9 and. 31;, switchv 3.8;..wires- .42,

and 20, filament l8, wiresitandi-A and supply line 23. As the filaments become hot, electronic emission therefrom will. result in. ionization of the. atmosphere inthe-armbulb; After; a brief initialperiod, the, starting switch 3.91is released and opens to break the starting, circuit described above, and the main are then strikes between the. electrodes 1 4, I 6; through the. ionized atmosphere, the current theniiowing through. the series operatingcircuit mentionedaboye.

In order to, operate the lampas an infrared generator only, a suitably insulated. conductor above toone terminalflfiof a. switch. indicated generally at 41, the other terminal, 48 of. the switch :being, connected by. a conductor 49. with a binding. post 50 from. which a. conductor. .51 leads to one end of avthird resistor5 1113 parallelto and hassubstantially the, same length as the arc bulb, il. Fromthe otherfendoi'jthis resistor, adwire 53 leads to. thejunctionj33jmeh-f tioned above, preferably passing, through the other side of the insulationtubeifi, When the switch 4? is closed, therefore, the resistor '52 shunts the-arc path betweenfthe electrodes 14 and It; the current then flowing through ajseris circuit comprising the line conductor: 22;. wire andv resistor 21, wire 2B and resistor 29, wire 45, switch In, wires 49. and 5!; resistor 52.1wires 53 and 3,4,and line conductor 23 [Hence the arc does not operate, but the three resistors 27, 29'and52 are connectedin.seriesacrosslthe lines 22, 23 to provide'infrared radiation.

The three elongated. resistors mentionedlaboye are combined in a singlegunit by enclosing them in ceramic material capable of being heatedby the resistors to a temperature at which infrared radiation isemitted. Also the connecting wires which extend between the opposite ends of the lampshould beainsulated these including it leads from the binding, post. al mentioned the wire. 42 in the starting circuitandthe wire, 34in the operating.c'ircuit..' Eoi-lTthesepur-poses th present invjentionm e us et a sin l 'rod or tube 5,4 of suitable. ceramicf material"having a. plurality of longitudinalbores orliolesoff the appropriate size toreceive'theelectricarelements to be insulated. Thlsceramicirod' mayhave; any desiredjcross-sectionalshape}. being shown" as substantially triangular; and is oisubstantially the same length asfand substantiallyparallel withthe lamp bulb" IL 'Ifhrefe large bores" or holesof diameter 'suificient to receive-the resistor coils 21, Hand 52 ertend longitudinally throughout the entire-length of the ceramic'rod 54- as shown in Fig's. '7 audit; mesa-arse holes being preferably arranged ad ritfitl ie corners of the triangularly' shaped The wires 34 and 42 pass through smaller ho es ran'ged betweenzthe la rgerbores mentioned abovei' The ultraviolet tube H- anathe ceramic tube 54 are rigidly assembledtogether dn: parallel,

closely spaced relation byisuitable'fmeandypreferably: clamps. which also; server: to transmiizheat to. the tube. H. "In theform showngflieachipazir of adjacent-ends ;of..the tube ro'dxare gripped by a pair of, approprlate-1y; shaped. clamping; elements; 5.5, the clamps being;suitably'tightened as bymeansof a pair; of: boltsbfivandi nut-e551, these :bolts. passing; through. the. clampsbetween the tube. and rod. These. clamps conductheat dire t f the ceramic u e- .5 o t Len of the burner tube H whiohsif. heated only by scl st eni wo l be s oe iha e rt of h m rw wou d n e se her in and th e r high pressure are wouldlnot be obtained; As theclarnps .55 do: not completely, surround the tube l-|.. but leave a; portion thereof. exposed, rings. 53 ay also. be slipped Lento. both ends. of the tubeouts'id theclarnps. i

As L'st'ated. abate, the combined; ultraviolet. tube andlceramic rodijare a sociated withal. cover element andjreflector to. 'fbrmla coverlunit that is pivoted. to the base by meansoflthe.pivot'v bracket '71. cover element may hayeanysuitable exteriorshape, and interiorly is're'cessed .or dished tomro'vide aca'vityand a 'reflecisdr therein. which reflects the ultraviolet radiation and/oriihfrared radiation outwardly from; the. lamp whenlthe cover unit-is in. operating positiohsaslshownhin .1. Preferably the boiler. unit includes an angular supporting platapart. of.lwhich. forms/a partition across the endloiithe cover element. sad plate cooperating;with, eicoyerjelementito provide a compartment adjae, tZtliepiyot mountlng' f'or the switches 39.and 4.1,), the supplycord 23; and the connections from .thesefelements to the. lamp and resistors; The assembledltubeiand rodLJare-secured atone endlof. the assemblytothe aforesaid partition and ar'e th us .inounted in the cavity of the cover unitinjassociation with the In the. preferred Iconst'ructionshown. in the drawings, the supporting. plate. mentioned above is madeiofistiif metal for greater. strength andis utilized'as the main. load carryingelementlof the cover unit, lt coinprises a fiat.sectionjfllclosing thel'endfo'f'thejdished cover element 61]} anda second ffi'at section 61 I. arranged. at right anglesto the. sectionlia and forming; apartition acrossthe end ofthe-coverl element '60; the platesection and .thacover. element thus co-operating to providea substantially closed compartmenttz. The plate section 59 issuitably attached.to-the pivot. bracket Tasby means of an auxiliary bracket 63' riveted orholted at 64 to thebraclsetfl and having. a flange fii-that-issecured .ingany;suitableimanner to the plate section 59, asfor example by. means of welding. The compartment 62 may be suitably ventilated, as by means of openings 66 in the plate section BI and similar openings 61 in the cover element 60; The cover element 69 is secured in the desired position by means of a flange or extension 68 of the bracket'63 which is shaped to fit closely against the cover element and is secured thereto by means of a screw 69. The cover element may be additionally secured in position by means of screws 19 which engage tabs ll formed on the upper edge of the plate section 6|.

In order to support the assembled ultraviolet tube l l and ceramic rod 54, and at the same time to insulate these elements and the various electrical connections described above from the metal supporting plate, thepartition 6i is formed with a large central opening 12 (Fig. and a base plate 13 and a terminalplate 14, both of suitable insulating material such as ceramic, are located on opposite sides of and assembled rigidly with the partition. The base plate :13 is held in spaced parallel relation with the partition! by means of tabs 15 turned at right angles to the place of the partition at the edges of the opening 12 and engaging the base plate "13. The terminal plate 14 is held in spaced relation with the partition 6| and base plate 13 by means of a spacer boss 16 which extends through the opening I2 in the partition and into engagement with the base plate 13, and by means of small lugs 11 at the corners of the terminal plate which engage the partition. The assembled tubeand rod and the plates 13 and 14 are secured rigidly with the partition 6! by means of a bolt 18 passing through an opening in the base plate 13 and through the boss '16, one end of the bolt being provided with an eye '19 through which one of the clamping bolts 56 passes and the other end of the bolt carrying a nut 80 that is screwed tight against the terminal plate I4. If desired, the surface of the base plate 13 may be recessed somewhat (Fig. 6) to receive the endsof the tube H and ceramic rod 54. The use of ceramic material for the plates 13 and 14 and the'spacing of these plates also serve to minimize the'amount of heat reaching the switches described below by radiation.

The. opposite ends of the lamp tube H and ceramic rod 54 are unsupported, but are preferably connected together by a suitable cap 8| which houses the electrical connections and also serves to conduct heat from the ceramic element to the ultraviolet lamp so as to improve its operation and at the same time to minimize heat losses to the atmosphere.

The supply cord 24 mentioned above isbrought into the compartment 62 through a suitable opening in the supporting plate section 59 in which th cord is preferably secured in any suitable manner as by means of a ferrule 82 of suitable insulating material and a strain clamp 83. (Fig. 11). The switches 39 and 41 are also mounted on the plate section 59 within the compartment 62, each switch casing being supported by a threaded stud 84 which passes through an opening in the plate 59 and is secured in position by means of lock nuts 85. The operating members 86 and 81 of the switches39 and 41 respectively are located outside the" compartment, and the plate 59 is preferably provided with circular louvers 88 to minimize the amount of heat reaching the switches by conduction. The binding posts 25, 3!, 36 and 59 mentioned above are located on the terminal plate 14, and the various electrical connections tothe lamp and to the ing of the cord 24 in its ceramic rod- 54 extend through holes in the terminal plate, through the opening 12in the partition 6 I, and through holes in the base plate 13 which are aligned with the various elements to which said conductorslead.

Preferably the ultraviolet humor I l is guarded by a suitable screen or guard which, in the form shown, comprises transverse wires 89 and 90 having their ends inserted through openings in the opposite edgesof the cover element 60 as shown in Fig.4, and alongitudinal wire 9| (Figs. 1 and 2) having its ends curved inwardly toward and around the ends of the lamp, these wires being suitably interconnected as by spot welding to form an integral protective guard. Preferably this guard is also employed as a means for coilingthe supply cord 24 when the lamp is not in use.v To this endthe wires 89 and 90 are turned substantially at right angles at the center line of the lamp as shown at 92 in Fig. 4 and are then turned again at right angles so that the central bight of each wire extends parallel with the axis of the burner tube toward the adjacent end of the tube as shown at 93 in Figs. 1 and 2. The wires 93 and 9i provide notches in which the supply cord 24 can-be coiled as pshown in Fig. 3 whenthe'lamp-is not in use. When the lamp is in operation, the cover'unit is prevented from swinging to closed position by means of a coil spring 94 having one end secured to the supporting-plate at 95 and its other end 96 projecting betweenthe adjacent pair of wires 93 and terminating in a hooked end 91 (see Fig. 1). Coilnotches depresses the spring element to the position shown in Fig. 3, where it is out of the way when the cover is closed. 7

It will be seen that when the supply cord is coiled inthe position shown in Fig. 3, the cover unit comprising all of the operating elements of the lamp can be swung downwardly about thepivot axis 8 into juxtaposition with the base to provide a closedhousing for all of these elements. For operation of the lamp, it is only necessary to swing the cover unit up about its pivot to the desired operating position and to uncoil the supply cord and plug it into a suitable source of current, this adjustment of the cover unit bein facilitated by the provision of a suitable handle here shown as a knob 98. For ultraviolet radiation, the starting switch member 86 is held closed temporarily, closing the switch 39 and completing the starting circuit as explained above for a'brief initial period, after which the member 8 6 is released and the switch 39 opens to start the are between the electrodes 14 and 18, the current then flowing through the series operating circuit described above. In case it is desired to operate the lamp as an infrared generator only, the switch member 81 is operated to close the switch 41, thereby completing a series circuit through the resistors 21, 29 and 52 as described above. In this case thestarting switch need not be operated and the arc does not start, since the filaments are not heated and since the voltage across the arc electrodes is only that across the resistor 52.

' Figs. 14 and 15 show a modified form of are burner that can be used in place of the one described above. The tubular glass bulb 109 corresponds to the bulb H described above. being mounted at each end by means of clamping members llll and sleeves 102 similar to the parts '55and 58 described above. Heat insulating material such'as sheet asbestos I03 surrounds the -clamping members l'lll. being interposed between gara es 'th'emand the sleeves i in so as to minimize tlheat 1 supporting ceramic plate 13,- M he tube I 08 is provided witharc electrodes I 05. I06 and starting i rnents 'lil'l, I08 preferably similar tothe elect on and filaments; It, I? and 18 described" efand. connected in circuits correspdndingjtdl li canbejeinployed f' es ed. "The location of "the.

grid prieyentsthe an I roin'melting thegla'ss wall cf the'tubefat highouthut.. f The .gridiifiill' can be mounted in any (suitable manner; "111' the To shown, the shank ,IIiljof the "molybdenum Wire extends parallel "to, the

.axi'sor 'thejtu'be and close to one side thereofjan'd iswelded at its. end to awire I I I which is mounted in thepress Hill at th "erablyboth wires ,lIQIl n 'jI' I"I arejen'closed in insulatingtubes "H3 an A respectively which may suitably :bemade of {glass Without such proteotionithe i'a 'a 'y', sometimes strike to and run 'dot inthewires T and III andfmeltIthe rid supporte en" thoug t e a 'fn'p electrically -'conne'cted "inthe lamp circuit,,par'- ticularly because the activating materialirom f the starting i'fil'anient 1168 mayfsputter ont'dthe grid suppbrt wires, I, 1 g 1 g "Sun lamps orth'ejtypeherein describedare used most "frequently *I'or the irradiation or relatively smallareas :ofthe lbQfiYTDhShOljt' peri'o ds fof time, and thelainp is-located rather close to he arget inches.

Henceinorder too 7 I I I from the irradiationfftreatment and in the "in- 'terest "or 'eflicient'iitilrzation ofthe i'energ'y of the lamp, it is very desirable "toconcerrtrate :as much energy. as pic iblfei in the target area and also top'htain subs n lly' 'uniform'energydis- 'trirbiitionthrough target area. These objectives pres'entja filcuit problem'in a lam'pof the "type described-above; "'Onl'y'a small part of the total energy of the ultraviolet burnerisemitted directly to thetarget iarea, and only a still smaller part 'oftheunfrared energy because part of the target ..area .is lmasked bythe ultraviolet burner.

inorder to utilize a 'gr'eater proportion of the available energy, therefore, reflection of both infrared and:ultravioletenergytothe target area is necessary.- However, reflection of both types of energy from the same reflecting surface inside theijcover (into the -target areainvolves the vdifiir d of the lamp. Prefrays as indicated by .the arrow I I9 .in broken lines, but that a large part of the ultraviolet energy would be reflected atsuchan angle as to mis's the-targetarea as indicated by thearrow I I20 in .solid lines.

New. referring to the lower half of Fig. 16, it will also be seen "that if small portions I 2| of the -.reflecting surface, located in its outer. part adjacent the ultraviolet generator, are disposed atan angle to the parabola H5 approaching parallelism with the parabola I I7, then the angle of reflection off the ultraviolet-rays as indicated by the. arrowijzc will bedecreased and the relflectedfl'rays 'will' more nearly approach parallelismwiththeaxis of theiparabola. In most cases,

howeVehithe target area will be too-large to be covered by a .para'llellbeam, and accordingly the refiecting portions I2I are preferably disposed at ianglesint'ermediate the .parabolas H5 and III andsuchithat ultraviolet rays-are still rejflectedther'efrom at {an angle to the axis of the parabola but in a direction that more closely parallels said axis than the direction that the same rays would assume when reflected froma surface corresponding .tothe parabola H5. The

angles of the portions I2I aresuitably adjusted so that the reflected ultraviolet radiation is concentrated on'the target area at the proper' 'distance'fromthe lamp, and is also distributedover the entire target area. It Will'be understood,;of course, that theupper half of the reflector-es seen intFig. i6 is similarly-constructed.

The resultant irregularity of the reflecting surface makes it 'diflicult to. drawor press the reflector to such perfection as to avoid strong and "weak spots in the light pat-tern onthe target. However; substantially uniform energy distribution can be obtained by the use of a large number of reflecting portions I2I of small size solas to produce a corresponding, number of overlapping [spots of light distributed over the-target area: The overlapping and merging of these spots may be facilitated by, making the reflecting portions 'I2I concave and preferably substantially spherical so that the reflected cones of light I22 are brought'toa'foc'us as indicate dat the points I23 and then diverge as'they approach the target. The'portions I2I may thus besubstantially circular in outline and present La dimpl'ed appearance.

Radiation from theinifrared generator is refle'cte'd in a substantially parallel beam bythe innerportion of thereflector conforming 'to the parabola II5, as indicated by the broken lines 124. It is to be remembered, however that in practice the generation of "infrared rays is not confined to a point at the'focus IiIfi, but they are emitted from th'eiwhole ceramic element 54 v andaccordin'gly the reflected rays are not conculty'thatthe two sources of energy are f'separate fined to the parallel beam I24. Also 'the portions I 21 of -theouter part of the reflecting surface are connected by intermediate portions I2 5 which are disposedat an angleto the parabola I I has the result of the drawing or pressingoperation. iInfrared rays str'ikingthe'se portions are refiected at an angle to the axis of the parabola as indicated by the bro'ken lines I26. Because of these overlapping reflections, the infrared-illumination'of the target is not confined to a ;spot corresponding t the beam I24 but is spread out over the target area, and more uniform energy distribution is produced. These effects may be enhanced, if desired, by the provision of a num-- ber of small dimples in the inner portion of the parabolic reflecting surface as indicated at I21, and these dimples'may be arranged in any desired manner in the interest of overall appearance of the reflector.

The reflector can be made by drawing or pressing a sheet of metal in a die, and the resulting product is preferably used alone as the cover 60 of the lamp. Fig. 17 shows the reflector in cross section in a plane at right angles to the axes of the generators. Apart from the dimples I2 I, the general or basic shape of the reflector is parabolic and conforms to'the curve. In a typical case,the dimples I21 varied from A to in diameter, and were curved on a radius of two inches. Under these conditions the depth of the depression at the center of the dimple was of the order of only 0.005 inch. The dimples can be arranged in rows extending in the direction of elongation of the reflector and more or less parallel to its outer edge or rim,. and the dimples in adjacent rows can be staggered if desired for closer spacing of the rows and utilization of a maximum part of the reflecting surface. Suchan arrangement is indicated diagrammatically in Fig. 18. Preferably the rows are continued around the end of the reflector.

Fig. 19 illustrates diagrammatically the results obtained with the above reflector on a target located about 18 inches from the lamp, only one side of the target being shown. The reflector 80, the infrared generator 54, and the ultraviolet generator II are constructed and located a described above. Ultraviolet rays emitted directly to the target are indicated by thelines. [28, The cones I22 of ultraviolet radiation reflected from the portions 12! are focused at I23 and then diverge to form substantially circular spots of illumination I29 on the target. These spots overlap each other as shown to provide an approximately uniform pattern of illumination which is superimposed on the approximately uniform pattern of direct illumination I28. Thus ultraviolet radiation is concentrated on and distributed over the target area. Infrared radiation, either along with ultraviolet radiation or alone, reaches and is distributed over the target area bylparallelbeam reflection indicated by the broken lines I24 and by nonparallel rays within the broken lines 126;

It will be understood that the inventionis not restricted to the embodiments illustrated-in the drawings and described above but is capable of other embodiments, and also that various changes can be made in the form, details of construction, and arrangement of the parts without departure. from itsspirit. Reference therefore should be had to the appended claims for a definition of the limits of'the invention.

What is claimed is:

1. A lamp of the type described comprising a base having a pivot mounting at one end, a cover unit movableinto juxtaposition with said base and cooperating therewith to form a housing, said cover unit comprising a supporting plate and a dished elongated cover element pivoted at one end on said mounting, said plate having a section forming a partition across the end of said cover element adjacent said pivot mounting and said element beyond said partition comprising a reflector, a substantially tubular ultraviolet lamp and an elongated ballast resistance means extending in spaced substantially parallel relation with one another and with said reflector and each having one end mounted on said partition, a lamp supply cord entering the compartment formed in the end of said cover unit behind said partition, and electrical connections between said cord, lamp and resistance means and enclosed in said compartment;

2. A lamp as defined in claim 1, said cover element being mounted on said plate and said plate being pivoted on said mounting.

3. A lamp of the type described comprising a base having a pivot mounting at one end, a cover unit movable about said pivot into juxtaposition with said base and cooperating therewith to form a housing, said cover unit comprising a dished elongated cover element pivoted at one end on said mounting and a. supporting plate part of which forms a partition acros the end of said dished cover element adjacent said pivot mounting, a substantially tubular ultraviolet lamp and a ballast resistance unit extending in spaced substantially. parallel relation with one another and with said cover. element. clamping means connecting the ends of said lamp and resistance unit together, means engaging said clamping means for mounting said lamp and resistance unit on said partition, reflector means on said cover element adjacent said lamp and resistance unit, a lamp supply cord entering the compartment formed in said cover unit behind said partition,

and electrical connections between said cord, lamp and unit and enclosed in said compartment.

4. A lamp as defined in claim 3, including an insulating base plate interposed between the ends of said lamp and unit and the partition and having recesses to receive said ends, said electrical connections passing through said insulating base.

5. A lamp as defined in claim 4, including a terminal plate of insulating material on the opposite side of said partition from said base plate, said partition, base and terminal plates, lamp and resistance unit all being secured in assembled relation by said means engaging said clamping means, and said base and-terminal plates and partition having alignedopenings for the passage of said electrical connections.

6. A lamp as defined in claim 3, said resistance unit comprising a ceramic element having substantially the same length as said lamp, said ceramic element having longitudinally extending bores fora plurality of resistors constituting said resistance and additional longitudinally extendingbores for connectors between the opposite ends of said lamp. f I

. GEORGE E. EMBSHOF'F.

GEORGE SPERTI. REFERENCES crrEn The followingreierences are of record in the file oi thispatent: i

I -"UNITED', srarEs PA'IEN'I'S Number Nadelson Oct. 25, 1949 

